Gwr Ransome & Rapier 36t Crane In 7mm

Dog Star

Western Thunderer
Steph,

Regarding motorising this kit, in discussion with Bob Alderman last week Bob mentioned that there was a member of the Bristol 0 Gauge Group who had a working breakdown crane... the name escaped him at the time.Any ideas?

regards, Graham
 

Old Buffer

Western Thunderer
There is another one that works and is radio controlled, I haven't seen it in action but by all accounts it is quite good. It was in use with the Hassel Harbour Bridge team (Alasager Railway Association) at the Spalding show. Don't know who's model it is but they are worth a try.
Alan
 

Steph Dale

Western Thunderer
Regarding motorising this kit, in discussion with Bob Alderman last week Bob mentioned that there was a member of the Bristol 0 Gauge Group who had a working breakdown crane... the name escaped him at the time.Any ideas?

Graham,
Not a clue I'm afraid - I'm not a member of B0GG.

Alan,
I think I've seen photos of a made up DJB crane on Hassel Harbour Bridge, so I'd guess it's that one. There are some thoughts about motorising in that kit's instructions, but I'm still not convinced it's an easy job: they hint that the results weren't entirely successfull. It's nice to know it can be doen though.

Steph
 

Dog Star

Western Thunderer
For no extra fee visitors to the Bristol 7mm show yesterday were treated to an animated discussion between Peter, myself and a bushwacker's hat masquerading as Steph Dale - in spite of Cynric's information I can confirm that Steph had neither pipe nor slippers. Said discussion concerned the fun awaiting those foolish enough to consider the new sport of "motorising a R&R 36T crane". So that those eager to play the game can experience the joys of the challenge here are some of the rules (noting that rules are changeable without notice and are not necessarily agreed by Steph, Peter or myself).

[1] required motion includes... travel, slew, derrick and lift. Crankshaft to rotate whenever any other motion is apparent (but excluding crane topple which ends the game).

[2] all motion to be DCC conrolled with interlocking to prevent conflicting motions (R&R did not design the crankshaft in such a way that all dogs can be engaged at the same time).

[3] Sound desirable although non-implementation until completion of restoration of GWR No. 2 is accepted (yet to be approved as a WT strategy for Mornington Crescent).

[4] working propping girders warrant immediate certification and a new, yet to be defined, WT-title (maybe Jordan could consider an Honorary degree of "Naughty Corner Monitor"?).

So how are we progressing? Not very well when we set off to the show although ideas were bubbling. Here are some photographs of the progress until we realised that following the instruction sequence was of minimal help in planning the installation of the motors. Current plan is to place motors for travel and for slew under the bed of the carriage with remaining motors in the cab / crab. However, space in the carriage is at a premium as can be seen from these photographs.

The first photograph shows the bed of the carriage (from underneath) together with the left hand and right hand sideframes for the rigid axles. The two small sub-assemblies are the housings for the propping girders. Attached to the carriage bed are three transoms which affix the bogie and the frame for the rigid axles. There is very little space, for a gearbox, between the crab pivot centre and the middle transom!

Crane-carriage-parts-1-web.jpg

The second photograph shows a side frame / solebar bottom plate in place (temporarily) ... and overlapping the three transoms. Soldering the side frame into place rather locks the transoms into the carriage underframe.

Crane-carriage-parts-2-web.jpg

The third photograph shows both side frames in place (temporarily) with a propping girder housing resting on the solebar - there is one housing at either end of the side frames. The more that is added.... the less space there seems to be.

Crane-carriage-parts-3-web.jpg

At least Steph, Peter and I agreed on a plan of action. First step is to move the transoms for the fixed axle frame to the outer ends of the side frames, this lengthens the space between the transoms by around 3cms. If necessary the centre portion of these two transoms can be removed although that requires a change to the method of attaching the fixed axle frame to the carriage. The reason for this change is to gain extra space for a worm drive gearbox and motor to provide slew drive (via a vertical shaft upon which the crab can rotate).

As the prototype is thought to slew at a rate of between 1 and 2 rpm then the reduction from motor speed to slew rate is considerable. All useful suggestions received.

After the slew motion the travel may be somewhat easier. The fold-up etch for the bogie frame was shown to Brian Clapperton (ABC Gears) with a request for a solution - favourable reply suggests a single motor lying parallel to the axles and with gears to drive both axles. I have to provide dimensions of the bogie so that Brian can confirm his "back-of-an-envelope" sketch. Fingers crossed.

regards, Graham
 

Dog Star

Western Thunderer
The weight tender carried the (six-ton) kentledge, together with lifting tackle (chains etc) and of course in the very early days all eight, and later four of the propping girders. The extra four girders were clearly dispensed with quite early in the crane's life, but I haven't been able to establish exactly when.

As we have moved onto assembly of the carriage this comment from Roger takes a step into the limelight. The kit provides propping girders made from etch brass... each girder being formed as an "I" beam from three pieces of etch plus a folded etch part to hold the screw jack. The intrigue is that the kit includes parts for eight propping girders.... together with "housings", attached to the bottom face of the solebar.... there are two housings with space for four girders (these housings are the sub-assemblies in the photographs which were posted earlier today). None of the GWR official photos appear to reveal either how the extra girders were carried or where the extra girders were located when the crane was in use.

Over to Roger for, I hope, chapter and verse on this puzzle.

regards, Graham
 

B.4411

Member
....here are some of the rules (noting that rules are changeable without notice and are not necessarily agreed by Steph, Peter or myself).

[1] required motion includes... travel, slew, derrick and lift. Crankshaft to rotate whenever any other motion is apparent (but excluding crane topple which ends the game).

[2] all motion to be DCC conrolled with interlocking to prevent conflicting motions (R&R did not design the crankshaft in such a way that all dogs can be engaged at the same time).

Hopefully the crankshaft will rotate in the correct direction, and permitted simultaneous motions will be restricted to the matching directions! (I appreciate that this may be tricky with the prototype not working, since it is not easy to determine which directions actualy match).

[3] Sound desirable although non-implementation until completion of restoration of GWR No. 2 is accepted (yet to be approved as a WT strategy for Mornington Crescent).

I'm afraid that that could be a while, then.

...The first photograph shows ... the two small sub-assemblies are the housings for the propping girders.

The correct name for these is the "girder boxes". Interestingly, they are actually removable on the prototype being bolted rather than rivetted into place, preumably to facilitate overhaul.
 

B.4411

Member
As we have moved onto assembly of the carriage this comment from Roger takes a step into the limelight. The kit provides propping girders made from etch brass... each girder being formed as an "I" beam from three pieces of etch plus a folded etch part to hold the screw jack. The intrigue is that the kit includes parts for eight propping girders.... together with "housings", attached to the bottom face of the solebar.... there are two housings with space for four girders (these housings are the sub-assemblies in the photographs which were posted earlier today). None of the GWR official photos appear to reveal either how the extra girders were carried or where the extra girders were located when the crane was in use.

Over to Roger for, I hope, chapter and verse on this puzzle.

regards, Graham

The eight girders (which were, incidentally, double ended; i.e., although a jackscrew was only present at one end of each girder, both ends had the fittings necessary to accomodate a jackscrew) would have been carried in the weight tender (the dropside wagon). Although I have never come across a photo which shows the stowage arrangements (the wagon was usually covered with a tarpaulin), I imagine that the eight girders would have been carried side-by-side at theend furthest from the crane, with the kentledge at the end of the wagon nearest the crane.

When the crane was being prepared for use, the girders would be craned out of the wagon and inserted into the girder boxes. To deploy all eight girders, four girders would be placed in each box, i.e., each of the two pockets in each box would have one girder inserted from each side as far as the centreline of the crane. If you look at the photo on the homepage of the BDCA (http://www.bdca.org.uk) you can see quite clearly how this is done (and it also confirms that all eight girders were still in use as late as 1925).

The girders are marked (painted) with a line to indicate their maximum permitted extension, which is actually the extension they would be at with two girders in the pocket, touching in the middle, and equally extended.

Three things I do not know relating to the girders are firstly when the GWR decided that four could remain in place during travel, secondly when it was that the other four were no longer routinely carried in the weight tender, and thirdly whether there were any rules about using four, as opposed to eight, girders in the early days. It may well be that if girders were deployed, then all eight were routinely used.

It is also not clear exactly how the girders were unloaded and inserted into the boxes; they are extremely heavy and it is likely that the crane itself must have been used for handling them.

After if became accepted practice to carry four girders in the boxes (which was, no doubt, to save setting-up time on site) the girderes were arranged to deploy thus, starting at the front pocket (ie nearest the jib runner): right, left, right, left. This enssured that the distance between the jackscrews was the same on both left and right sides.

The pockets are fitted with rollers at the bottom of the outboard ends, but the insertion and extension of the girders is manual (later cranes had ratchet mechanisms). It is at least a two man job to pull a girder out, and harder still to retract it. The easiest technique I have found for the latter is actually to tie a rope through the hole for the jackscrew at the inboard end prior to pulling the girder out; this can them be used from the opposite side to pull it back afterwards.
 

Dog Star

Western Thunderer
The eight girders would have been carried in the weight tender. To deploy all eight girders, four girders would be placed in each box, i.e., each of the two pockets in each box would have one girder inserted from each side as far as the centreline of the crane. If you look at the photo on the homepage of the BDCA (http://www.bdca.org.uk) you can see quite clearly how this is done (and it also confirms that all eight girders were still in use as late as 1925).
Now that you mention this... I have soomed into the picture and I now understand the way in which the girders are installed and used. Thank you for explaining this point.

The girders are marked (painted) with a line to indicate their maximum permitted extension, which is actually the extension they would be at with two girders in the pocket, touching in the middle, and equally extended.
Sorry to ask... what is the length of the girder from jack screw housing to jack screw housing? and how far is the line from the end of the girder?

The pockets are fitted with rollers at the bottom of the outboard ends.
I have now found the rollers in one of the photos (which come with the kit). I guess at 2" diameter.... how does that compare with reality?

The photos suggest that there is a locking device in the girder boxes - to prevent the girders from moving when the crane is travelling. I guess that such devices date from the decision to allow the crane to travel with the propping girders in the girder boxes. What do you think of that idea?

How are the jack screws operated?

Thank you and regards, Graham
 

Old Buffer

Western Thunderer
Further to the working breakdown cranes, David Hampson of Oldham King Street Parcels has a working model of one. The layout is DCC so it probably works through that, unlike Hassle Harbour which is radio controlled, didn't see it in action but there is a video of it.
Alan
 

B.4411

Member
Sorry to ask... what is the length of the girder from jack screw housing to jack screw housing? and how far is the line from the end of the girder?


I have now found the rollers in one of the photos (which come with the kit). I guess at 2" diameter.... how does that compare with reality?

The photos suggest that there is a locking device in the girder boxes - to prevent the girders from moving when the crane is travelling. I guess that such devices date from the decision to allow the crane to travel with the propping girders in the girder boxes. What do you think of that idea?

How are the jack screws operated?

Thank you and regards, Graham

The overall length of each girder is exactly the same as the overall width of the carriage (and for that matter the top surface of the girder boxes).

The marking to indicate maximum extension is on the centreline of the girder (so if two were inserted in the same pocket, one from either side, and pushed in until they touched in the middle whilst projecting equally on each side, the painted line would just be visible).

The rollers on the outer end of the bottom surface of each pocket are (from memory) approx 3" diameter.

The locking system used on No 2 consists of eight small blocks bolted to the plate which divides each box into two pockets. There is one block per side per pocket, and they are bolted in pairs with a single bolt which passes through the vertical plate which seperates the girder box into the two pockets. Not easy to describe in words; I will try to locate and post a photo when I get the chance.

The jackscrews are simply large vertical screws which pass downwards through the ends of the girders. They are approx 4" diameter and have an Acme (square) thread. The top (ie the head) is flat (like a cheesehead screw but without the slot) and is cross-drilled on two axes for a bar to pass through. The bottom is drilled co-axially to take a retaining screw for the square cast steel foot or pad (although these never seem to have remained in place - it appears that almost always they were carried as loose items on the jib runner). The screws are pulled down manually with bars. It is hard work, and in use packing would always be built up to a height as close as possible to the jackscrew foot in order to minimise the amount of "mandraulic" input required!

I will try to post some photos when I get the chance.
 

Dog Star

Western Thunderer
Excellent reply :thumbs: .
I think that I can use the information as is.... although I understand that Steph Dale is going to make the girders move under DCC control - and the screw jacks go up / down just as soon as he can create carbon-based bipedal life forms of an accurate size.

regards, Graham
 

Dog Star

Western Thunderer
Some potential good news regarding the travel of the carriage.

We took the partly assembled carriage and a handful of etch parts to the recent Bristol 0 gauge show and had a discussion with Steph regarding options for motorising the travel aspect of the carriage. Brimming with possibilities the next port of call was ABC Gears. After a long discussion about gear ratios (big), maximum speed (slow) and gauge (32mm and 33mm depending upon day of the week) the verdict was delivered - "possibly" (and not a quantum or quark in sight). A few days later I sent a diagram of the space envelope of the bogie frame to ABC Gears with an outline specification.... a self-contained motor bogie capable of moving the crane (weight circa 2.5Kg) with DCC decoder within the bogie envelope and all to ABC quality.

Today I have had a further discussion with ABC Gears and things do not look bad. Hopefully a positive decision will be delivered circa 14th February.

Steph, how does this approach fit into your intentions for the two SR cranes?

regards, Graham
 

Steph Dale

Western Thunderer
Graham,

I've given up on the carbon-based bipeds and gone for silicon-based instead, I think their higher density will add to the impression of inertia when in use...

On a more serious note, I did work out how to make the jacks deploy in model form by using a couple of bell cranks - the problem is analogous to making level-crossing gates work. But being tight for space and now knowing that the real things were deployed by muscle power, I shall do the same with my model.

In terms of drive, I'm back to where I was. These things are going to spend most of their life being hauled around, so I'm sticking with idler drive. I'll use a smallish Mashima motor and High Level gearbox of high ratio to get the speed and power necessary. The idler drive will work instead of needing to control a clutch. I'll drive as per the prototype, two axles under the centre of the carriage.

For me the main 'hmm?' point out of our conversation at the BOGG show was how many decoders to use. I appreciate the advantages of using many (only two wires through the rotating joint) and the disadvantages (cost, consisting). I'm mulling that over at the moment...

Steph
 

Dog Star

Western Thunderer
Aware that there are at least two WT readers who have bought this kit... some news.

Yesterday the postie staggered up the garden path with a packet from Sanspareil.... lots of castings and a letter. The letter notes that some of the original castings were not as accurate as one might like... so here are some replacements. Further, the letter informs that there are one or two new castings to make life easier, such as a crab pivot.

Top marks to Iain for listening to customers and responding so well.
 

alcazar

Guest
That's quite brilliant.

If only ALL kit manufacturers were as good. David Parkins' service is as good..........
 

Steph Dale

Western Thunderer
Graham,

I know we haven't discussed this project of late - which may be influenced by my decision to finish my models as unpowered trains, but I have just been pointed to some wonderful video(s) of a pair of R&R 30tonners in use in Sri Lanka. It will give you a great idea of what's actually required to animate them properly...!


Steph
 
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